1. Field of Invention
The present invention relates to a three dimensional circuit body having a conductive circuit pattern formed on a three-dimensionally curved or bent surface of, for example, various vehicle body frames or the like; and a method of manufacturing a three-dimensional circuit body having a circuit pattern formed on such a curved or bent surface.
2. Related Art
Recent years, a number of wire harness have been used in the vehicle such as automotive vehicle for mounting various electronic equipment and connecting between such electronic equipment. Therefore, wiring operation of wire harness is performed in the production line or during maintenance operation, and such wiring operation has been consuming time and manpower.
Conventionally, printed-wiring boards have often been used for electronic equipment. However, since the conventional circuit pattern is manufactured in such a manner that a flat circuit pattern is formed by corroding a copper foil formed on the flat circuit board by etching technique, it cannot be employed to a member having a curved or bent surface, such as a car body frame.
Accordingly, a various proposals have been presented as a method of forming a circuit pattern on the circuit board. For example, in xe2x80x9cMethod of manufacturing injection molded circuit componentsxe2x80x9d disclosed in Japanese Patent Laid-Open No.4-239795, a first resin layer containing a catalyst for enhancing a property to accept plating is formed by injection molding. Then, a second resin layer being impregnated with oil for disabling application of plating thereon is formed on the upper surface of the first resin layer, thereby fabricating the circuit component body with the first resin layer exposed along the position where the circuit pattern is to be formed.
Then electroless copper plating is applied on the upper surface of the circuit component body, and a layer of conductive material to be a circuit pattern is laminated on the upper surface of the first resin layer to complete the injection molded circuit component.
xe2x80x9cResin composition for electric resinxe2x80x9d disclosed in Japanese Patent Laid-Open No. 5-325637 relates to a conductive material for forming a circuit pattern, that is, a mixture of metal fibers such as copper fibers, brass fibers, aluminium fibers, or stainless fibers; low-melting metals such as generally used solder, high temperature solder, or low temperature solder; flux; and a synthetic resin.
The xe2x80x9cMethod of manufacturing circuit boardxe2x80x9d disclosed in Japanese Patent Laid-Open No.8-204315 comprises the steps of forming a layer of metallic plate as a circuit body on the molding surface of the mold by electrolytic plating, pressing the mold against the substrate formed of a thermoplastic resin, heating the mold and holding it onto the substrate to adhere the circuit body onto the substrate by heat, and then separating the mold from the substrate after the substrate is cooled down so that the circuit body is transferred onto the substrate.
In the xe2x80x9cMethod of manufacturing circuit boardxe2x80x9d disclosed in Japanese Patent Laid-Open No. 4-239795, however, palladium chloride is used as a catalyst for electroless plating, which is very expensive, thereby increasing the cost of the injection molded circuit component.
In addition, since the second resin layer has to be formed on the first resin layer so that the portion of the first resin layer to be applied a circuit pattern is left exposed, both the structure of the mold and the manufacturing steps are complicated, and thus it has been difficult to form a circuit pattern on the three dimension structure of complex configuration such as a car body frame.
As regards the xe2x80x9cResin composition for electric resinxe2x80x9d disclosed in Japanese Patent Laid-Open No.5-325637, there has been a problem in that low-melting metals used in this composition are expensive, which is one of the reasons of high cost. In addition, as a recent tendency, it is required to consider the environmental issues for every product. However, using an alternative material to lead compound that is not preferable for environment further increases the cost.
In the xe2x80x9cMethod of manufacturing circuit boardxe2x80x9d disclosed in Japanese Patent Laid-Open NO.8-204315, since a specific mold for forming the circuit body have to be provided and an additional step of transferring the circuit body to the circuit board by pressing the mold onto the circuit board is included, there has been a problem in that these circumstances conspire to increase the cost. In other words, it has been difficult to form a circuit pattern easily on the surface of the three-dimensional structure along the surface of the complex profile such as the car body frame.
Accordingly, with the circumstances described above in view, it is an object of the invention to provide a three-dimensional circuit body in which a circuit pattern is formed along the surface of the substance of a three-dimensional configuration, such as a car body frame, and the method of manufacturing the same.
The problems described above associated with the present invention may be solved by the third-dimensional circuit body comprising a car body frame having a three dimensional configuration, an insulating layer formed along the surface configuration of the car body frame, and a circuit pattern formed by applying and simultaneously curing conductive paste on the surface of the insulating layer.
According to the three-dimensional circuit body having the structure described above, since the circuit pattern is formed by the steps of forming an insulating layer along the corrugated surface for example of the car body frame, and applying and simultaneously curing conductive paste along the surface of the insulating layer, conductive paste can be applied along the surface configuration of the car body frame even when the surface configuration is complicated, thereby simplifying the formation of the circuit pattern and reducing the cost therefor.
In the three-dimensional circuit body of the invention, the insulating layer is preferably any one of a hard material formed along the surface configuration of the car body frame, a soft material to be adhered along the car body frame, and a thin film formed in a layer. In the three-dimensional circuit body of the invention, the circuit pattern is preferably formed in a configuration being separated or being intersected with respect to each other.
According to the three-dimensional circuit body of the invention, the mold for forming the circuit pattern is not necessary and the circuit pattern may be formed in a configuration being separated or partly intersected depending on the configuration of the portion to which the circuit pattern is applied, thereby reducing the cost and enhancing the flexibility of wiring.
The problems associated with the present invention may be solved by a method of manufacturing a three dimensional circuit body by forming a circuit pattern on the surface of a three-dimensional car body frame by discharging conductive paste on the surface of the three-dimensional substance while moving a discharging unit, comprising the steps of moving the discharging unit along the surface configuration of the insulating layer formed along the three-dimensional car body frame, discharging the conductive paste from said discharging unit onto said insulating layer, and curing said conductive paste by a curing unit moving unitarily with said discharging unit simultaneously with discharging operation.
According to the method of manufacturing the three-dimensional circuit body having a structure described above, the circuit pattern is formed by forming an insulating layer on the surface of the three-dimensional car body frame, moving the discharge unit and curing unit simultaneously along the surface thereof, and discharging conductive paste from the discharge unit onto the insulating layer while curing it simultaneously. Therefore, even when the surface of the car body frame is corrugated, the circuit pattern may be formed along the configuration thereof, thereby simplifying the manufacturing process and reducing material to be used.
In the method of manufacturing the three-dimensional circuit body, the conductive paste is preferably made by adding phenol resin to conductive metal powder so that the surface thereof is changed to have an insulating property when cured.
According to the method of manufacturing the three-dimensional circuit body of the invention, the circuit pattern may be made in the intersected pattern, thereby increasing flexibility of the design.